Crystallographic fragment screening - improvement of workflow, tools and procedures, and application for the development of enzyme and protein-protein interaction modulators

One of the great societal challenges of today is the fight against diseases which reduce life expectancy and lead to high economic losses. Both the understanding and the addressing of these diseases need research activities at all levels. One aspect of this is the discovery and development of tool compounds and drugs. Tool compounds support disease research and the development of drugs. For about 20 years, the discovery of new compounds has been attempted by screening small organic molecules by high-throughput methods. More recently, X-ray crystallography has emerged as the most promising method to conduct such screening. Crystallographic fragment-screening (CFS) generates binding information as well as 3D-structural information of the target protein in complex with the bound fragment. This doctoral research project is focused primarily on the optimization of the crystallographic fragment screening workflow. Investigated were the requirements for more successful screening campaigns with respect to the crystal system studied, the fragment libraries, the handling of the crystalline samples, as well as the handling of the data associated with a screening campaign. The improved CFS workflow was presented as a detailed protocol and as an accompanying video to train future CFS users in a streamlined and accessible way. Together, these improvements make CFS campaigns a more high-throughput method, offering the ability to screen larger fragment libraries and allowing higher numbers of campaigns performed per year. The protein targets throughout the project were two enzymes and a spliceosomal protein-protein complex. The enzymes comprised the aspartic protease Endothiapepsin and the SARS-Cov-2 main protease. The protein-protein complex was the RNaseH-like domain of Prp8, a vital structural protein in the spliceosome, together with its nuclear shuttling factor Aar2. By performing the CFS campaigns against disease-relevant targets, the resulting fragment hits could be used directly to develop tool compounds or drugs. The first steps of optimization of fragment hits into higher affinity binders were also investigated for improvements. In summary, a plethora of novel starting points for tool compound and drug development was identified

Evaluation of docking performance in a blinded virtual screening of fragment-like trypsin inhibitors

International audienceIn this study, we have "blindly" assessed the ability of several combinations of docking software and scoring functions to predict the binding of a fragment-like library of bovine trypsine inhibitors. The most suitable protocols (involving Gold software and GoldScore scoring function, with or without rescoring) were selected for this purpose using a training set of compounds with known biological activities. The selected virtual screening protocols provided good results with the SAMPL3-VS dataset, showing enrichment factors of about 10 for Top 20 compounds. This methodology should be useful in difficult cases of docking, with a special emphasis on the fragment-based virtual screening campaigns

Mammogram history in Nigerian women: Age-related risk factors for breast cancer and educational implications

Background: Breast cancer accounts for 25% of diagnosed cancers and 20% of cancer-related mortality in women from sub-Saharan Africa. Given the early onset of breast cancer in African women, there is a need to better understand how age-related risk factors contribute to mammography uptake in this population. Aim: To identify age-related risk factors for breast cancer associated with previous uptake of mammograms in asymptomatic Nigerian women and consider implications for health education campaigns. Method: Participants comprised 544 asymptomatic Nigerian women (aged 28–75 years) responding to breast cancer public awareness campaigns, by presenting for baseline or screening mammography at a local hospital. Information about mammography history and age-related risk factors (menarche, menopausal and chronological age) were obtained by interviewing the participants face-to-face, before proceeding with mammography. Hierarchical logistic regression was used to estimate the odds of previous mammograms based on the age-related risk factors. Results: The likelihood of previous mammography screening increased by a factor of 1.07 (95% confidence interval [CI]: 1.00–1.14) for every year older chronologically and decreased by a factor of 1.12 (95% CI: 1.24–1.01) for every year older at menarche. Age at menarche partly mediated the relationship between chronological age and mammography history (effect = –0.01, 95% CI: –0.01, –0.00). Women with a history of breast cancer were 6.11 times more likely to have previously undertaken mammography screening (95% CI: 2.49–14.97). Age at menopause and age at first confinement were unrelated to mammography history. Conclusions: Nigerian women may recognise the need for mammograms because of adverse age-related risk factors for breast cancer, notably menarche and chronological age. However, awareness of menopausal age as a risk factor and basis for mammography screening may be deficient. It is therefore recommended that public awareness campaigns should emphasise the importance of older menopausal age in breast cancer risk and as a basis for requesting mammograms

HBV Testing and Vaccinations among Asian and Pacific Islander Patients: Understanding the Impact of the San Francisco Hepatitis B Free Campaign on Physician Awareness

Background and Significance: One in 12 Asian and Pacific Islanders (APIs) are infected with hepatitis B (HBV). APIs represent one-third of the population in San Francisco. San Francisco Hep B Free (SFHBF), a citywide collaboration, works to educate physicians and the community on the importance of hepatitis B among APIs through increasing awareness, education and the availability of screening and vaccinations. The purpose of this paper was to qualitatively assess the perceived impact of SFHBF on the awareness and attitudes of physicians regarding screening and vaccination of APIs. Methods: Twenty physicians (n=20) participated in key informant interviews about HBV awareness and involvement with SFHBF. The questions focused on physician attitudes and practice towards HBV screening, vaccination and follow-up care, communication with patients about HBV, and awareness and effectiveness of the SFHBF outreach efforts. Results: Findings highlighted SFHBF’s impact on physicians’ sensitivity and awareness. Overall, physicians were increasing their HBV screening and vaccination rates among their API patients. Physicians noted the need for continual support to prioritize HBV screening and vaccination among their API patients. Conclusion: The findings of this study are important for understanding the impact of public health campaigns on physician attitudes and practices regarding HBV education, screening, and vaccinations among their API patients

Cost of HPV screening at community health campaigns (CHCs) and health clinics in rural Kenya.

BACKGROUND:Cervical cancer is the most frequent neoplasm among Kenyan women, with 4800 diagnoses and 2400 deaths per year. One reason is an extremely low rate of screening through pap smears, at 13.8% in 2014. Knowing the costs of screening will help planners and policymakers design, implement, and scale programs. METHODS:We conducted HPV-based cervical cancer screening via self-collection in 12 communities in rural Migori County, Kenya. Six communities were randomized to community health campaigns (CHCs), and six to screening at government clinics. All HPV-positive women were referred for cryotherapy at Migori County Hospital. We prospectively estimated direct costs from the health system perspective, using micro-costing methods. Cost data were extracted from expenditure records, staff interviews, and time and motion logs. Total costs per woman screening included three activities: outreach, HPV-based screening, and notification. Types of inputs include personnel, recurrent goods, capital goods, and services. We costed potential changes to implementation for scaling. RESULTS:From January to September 2016, 2899 women were screened in CHCs and 2042 in clinics. Each CHC lasted for 30 working days, 10 days each for outreach, screening, and notification. The mean cost per woman screened was $25.00 for CHCs [median:$25.09; Range: $22.06-30.21] and$29.56 for clinics [$28.90;$25.27-37.08]. Clinics had higher costs than CHCs for personnel ($14.27 vs.$11.26) and capital ($5.55 vs.$2.80). Screening costs were higher for clinics at $21.84, compared to$17.48 for CHCs. In contrast, CHCs had higher outreach costs ($3.34 vs.$0.17). After modeling a reduction in staffing, clinic per-screening costs ($25.69) were approximately equivalent to CHCs. CONCLUSIONS:HPV-based cervical cancer screening through community health campaigns achieved lower costs per woman screened, compared to screening at clinics. Periodic high-volume CHCs appear to be a viable low-cost strategy for implementing cervical cancer screening

Determinants of Acceptance of Cervical Cancer Screening in Dar es Salaam, Tanzania.

To describe how demographic characteristics and knowledge of cervical cancer influence screening acceptance among women living in Dar es Salaam, Tanzania. Multistage cluster sampling was carried out in 45 randomly selected streets in Dar es Salaam. Women between the ages of 25-59 who lived in the sampled streets were invited to a cervical cancer screening; 804 women accepted and 313 rejected the invitation. Information on demographic characteristics and knowledge of cervical cancer were obtained through structured questionnaire interviews. Women aged 35-44 and women aged 45-59 had increased ORs of 3.52 and 7.09, respectively, for accepting screening. Increased accepting rates were also found among single women (OR 2.43) and among women who had attended primary or secondary school (ORs of 1.81 and 1.94). Women who had 0-2 children were also more prone to accept screening in comparison with women who had five or more children (OR 3.21). Finally, knowledge of cervical cancer and awareness of the existing screening program were also associated with increased acceptance rates (ORs of 5.90 and 4.20). There are identifiable subgroups where cervical cancer screening can be increased in Dar es Salaam. Special attention should be paid to women of low education and women of high parity. In addition, knowledge and awareness raising campaigns that goes hand in hand with culturally acceptable screening services will likely lead to an increased uptake of cervical cancer screening

Interventions to Promote Cancer Awareness and Early Presentation: Systematic Review

Low cancer awareness contributes to delay in presentation for cancer symptoms and may lead to delay in cancer diagnosis. The aim of this study was to review the evidence for the effectiveness of interventions to raise cancer awareness and promote early presentation in cancer to inform policy and future research. We searched bibliographic databases and reference lists for randomised controlled trials of interventions delivered to individuals, and controlled or uncontrolled studies of interventions delivered to communities. We found some evidence that interventions delivered to individuals modestly increase cancer awareness in the short term and insufficient evidence that they promote early presentation. We found limited evidence that public education campaigns reduce stage at presentation of breast cancer, malignant melanoma and retinoblastoma

Assessing Creative Media's Social Impact

Examines case studies of documentary film as a means of outreach and community engagement in the age of social media. Offers a model for assessing impact based on quality and ability to enhance awareness, engagement, and social movement and effect change